Amphiphilic block copolymer-modified epoxy resins and adhesives made therefrom

Abstract

A curable adhesive epoxy resin composition including (a) an epoxy resin; (b) an amphiphilic block copolymer containing at least one epoxy resin miscible block segment and at least one epoxy resin immiscible block segment; wherein the immiscible block segment comprises at least one polyether structure provided that the polyether structure of said immiscible block segment contains at least one or more alkylene oxide monomer units having at least four carbon atoms; in an amount such that when the epoxy resin composition is cured, the bond strength of the resulting cured epoxy adhesive resin composition increases compared to an epoxy resin composition without said amphiphilic polyether block copolymer; and (c) at least one curing agent. The amphiphilic block copolymer is preferably an all polyether block copolymer such as a PEO-PBO diblock copolymer or a PEO-PBO-PEO triblock copolymer.

1. A curable adhesive epoxy resin composition comprising
 (a) an epoxy resin; 
 (b) an amphiphilic block copolymer containing at least one epoxy resin miscible block segment and at least one epoxy resin immiscible block segment; wherein the immiscible block segment comprises at least one polyether structure provided that the polyether structure of said immiscible block segment contains at least one or more alkylene oxide monomer units having at least four carbon atoms; in an amount such that when the epoxy resin composition is cured, the bond strength of the resulting cured epoxy adhesive resin composition increases compared to an epoxy resin composition without said amphiphilic polyether block copolymer; and 
 (c) at least one curing agent; 
 wherein the at least one epoxy resin miscible block segment contains a polyethylene oxide block, a propylene oxide block, or a poly(ethylene oxide-co-propylene oxide) block; and the at least one epoxy resin immiscible block segment contains a polybutylene oxide block, a polyhexylene oxide block, or a polydodecylene oxide block. 
 
     
     
       2. A curable adhesive epoxy resin composition comprising
 (a) an epoxy resin; 
 (b) an amphiphilic block copolymer containing at least one epoxy resin miscible block segment and at least one epoxy resin immiscible block segment; wherein the immiscible block segment comprises at least one polyether structure provided that the polyether structure of said immiscible block segment contains at least one or more alkylene oxide monomer units having at least four carbon atoms; in an amount such that when the epoxy resin composition is cured, the bond strength of the resulting cured epoxy adhesive resin composition increases compared to an epoxy resin composition without said amphiphilic polyether block copolymer; and 
 (c) at least one curing agent; 
 wherein the at least one of the epoxy resin miscible block segments of the amphiphilic block copolymer is a poly(ethylene oxide); and the at least one of the epoxy resin immiscible block segments of the amphiphilic block copolymer is a polybutylene oxide). 
 
     
     
       3. A curable adhesive epoxy resin composition comprising
 (a) an epoxy resin; 
 (b) an amphiphilic block copolymer containing at least one epoxy resin miscible block segment and at least one epoxy resin immiscible block segment; wherein the immiscible block segment comprises at least one polyether structure provided that the polyether structure of said immiscible block segment contains at least one or more alkylene oxide monomer units having at least four carbon atoms; in an amount such that when the epoxy resin composition is cured, the bond strength of the resulting cured epoxy adhesive resin composition increases compared to an epoxy resin composition without said amphiphilic polyether block copolymer; and 
 (c) at least one curing agent; 
 wherein the amphiphilic block copolymer is poly(ethylene oxide)-b-poly(butylene oxide) or poly(ethylene oxide)-b-poly(butylene oxide)-b-poly(ethylene oxide). 
 
     
     
       4. The composition of  claim 1  wherein the amphiphilic block copolymer has a number average molecular weight of from 1000 to 30,000. 
     
     
       5. The composition of  claim 1  wherein the ratio of the epoxy resin miscible segments of the amphiphilic block copolymer to the epoxy resin miscible segments of the amphiphilic block copolymer is from 10:1 to 1:10. 
     
     
       6. The composition of  claim 1  wherein the amphiphilic block copolymer is present in an amount of from 0.1 weight percent to 30 weight percent based on the weight of the composition. 
     
     
       7. The composition of  claim 1  wherein the epoxy resin is selected from the group consisting of polyglycidyl ethers of polyhydric alcohols, polyglycidyl ethers of polyhydric phenols, polyglycidyl amines, polyglycidyl amides, polyglycidyl imides, polyglycidyl hydantoins, polyglycidyl thioethers, epoxidized fatty acids or drying oils, epoxidized polyolefins, epoxidized di-unsaturated acid esters, epoxidized unsaturated polyesters, and mixtures thereof. 
     
     
       8. The composition of  claim 1  wherein the epoxy resin is a glycidyl polyether of a polyhydric alcohol or a glycidyl polyether of a polyhydric phenol. 
     
     
       9. The composition of  claim 1  wherein the epoxy resin is selected from the group consisting of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexyl carboxylate; 1,2-epoxy-4-vinylcyclohexane; bis(7-oxabicyclo[4.1.0]hept-3-ylmethyl hexanedioic acid ester; 3,4-epoxycyclohexanecarboxylate methyl ester; and mixtures thereof. 
     
     
       10. The composition of  claim 1  including a homopolymer of identical composition to the epoxy resin immiscible block segment. 
     
     
       11. The composition of  claim 1  including a homopolymer of identical composition to the epoxy resin miscible block segment. 
     
     
       12. The composition of  claim 1  wherein the polyepoxide has an epoxide equivalent weight of from 150 to 3,000. 
     
     
       13. The composition of  claim 1  including a curing catalyst. 
     
     
       14. A process for preparing a curable adhesive epoxy composition comprising mixing
 (a) an epoxy resin; 
 (b) an amphiphilic block copolymer containing at least one epoxy resin miscible block segment and at least one epoxy resin immiscible block segment; wherein the immiscible block segment comprises at least one polyether structure provided that the polyether structure of said immiscible block segment contains at least one or more alkylene oxide monomer units having at least four carbon atoms; in an amount such that when the epoxy resin composition is cured, the bond strength of the resulting cured epoxy adhesive resin composition increases compared to an epoxy resin composition without said amphiphilic polyether block copolymer; and 
 (c) at least one curing agent; 
 wherein the at least one of the epoxy resin miscible segments of the amphiphilic block copolymer is a poly(ethylene oxide); and the at least one of the epoxy resin immiscible segments of the amphiphilic block copolymer is a poly(butylene oxide). 
 
     
     
       15. Two or more substrates bonded with the adhesive composition of  claim 1 . 
     
     
       16. The composition of  claim 1  including a filler. 
     
     
       17. The composition of  claim 16  wherein the filler is selected from the group consisting of fumed silica, colloidal silica, bentonite clay, mica, atomized aluminum powder, and mixtures thereof. 
     
     
       18. The composition of  claim 16  wherein the concentration of filler is up to 300 phr. 
     
     
       19. The composition of  claim 1  wherein the amphiphilic polyether block copolymer is selected from the group consisting of a diblock, a linear triblock, a linear tetrablock, a higher order multiblock structure; a branched block structure; or a star block structure.